Papa, I almost forgot, really nice job on the wing attachment, and spar reinforcement. I'll give it a whirl on the new one.
One thing I did find on mine. Loops tend to make the wings flex badly at the fuselage. Ok I know it's not a sport plane but I had to see if it would do it.
Anyhow, my point being, I epoxied my wings in place and was forever touching up the joints, as it seemed every flight would crack the joint after those loops. Could be I did more structural damage then cosmetic in doing loops and what I was seeing was just a forewarning of what was going to happen.